Synthesis of 1,3,4-oxazaphospholines based on phosphorylated carbamates

Abstract

Addition of alcohols to bis(chloromethyl)phosphinoyl isoeyanate, as well as the re.action of bis(chloromethyl)phosphinoyl chloride with urethanes or their silylated derivatives, gave the corresponding phosphorylated carbamates which undergo cyclization into 1,3,4-oxazaphospholines under the action of Et3N.Key words: bis(chloromethyl)phosphinoyl chloride(isocyanate), phosphorylated carbamates, heterocyciization, 1,3,4-oxazaphospholines.At present, we are developing methods for the synthesis of polyheterophosphacyclanes with an endocyclic P--C bond. These are based on intramolecular transformations of polyfunctional derivatives of the four-coordinate phosphorus atom. 1 In particular, various saturated and unsaturated phosphacyclanes with the P--C bond can be obtained by combination ofa chloromethyl group and urea (thiourea, acylamide, etc.) fragments in a molecule. Functionalized chloromethylphosphonates (-phosphinates) cart be synthesized by addition of amines, thiols, hydrazines, phosphines, and other protonic nucleophiles to (thio)phosphonoyl(phosphinoyl) iso(thio)-cyanates. 1-5 We undertook synthesis of phosphorylated carbamates bearing the chloromethyl groups at the phosphorus atom and attempted to perform their cyclization.We developed three methods for the synthesis of the target products. Bis(chloromethyl)phosphinoyl isocyanate (1) easily adds alcohols to give phosphorylated carbamates (2, 3).The structures and compositions of compounds 2 and 3 were confirmed by data from NMR and IR spectroscopy and elemental analysis. Taking into account the data obtained by us earlier, * we attempted to synthesize compounds 2 and 3 by phosphorylating silylated carbamates. The reaction of bis(chloromethyl)-phosphinoyl chloride (4) with ethyl N-trimethylsilylcarbamates 7 (5) easily proceeds with the elimination of chlorotrimethylsilane to give product 3. In addition, compound 3 cart be obtained by phosphorylation of ethyl carbamate (6) with chloride 4 in the absence of a base. + H2NCOOEt= 3 6In the presence of tfiethylamine, carbamates 2 and 3 easily split off hydrogen chloride to transform into the corresponding 1,3,4-thiazaphospholines (7, 8). (3)The structures and compositions of compounds 7 and 8 were confirmed by data from NMR and IR spectroscopy and elemental analysis. Note that the protons of the endo-and exocyclic methylene groups manifest themselves as one doublet in the IH NMR spectra. Experimental31p NMR spectra were recorded on a Bruker MSL-400 spectrometer (161.97 MHz) with 85% H3PO 4 as the external

Synthesis of intermediate compounds with P-N bond from (thio)carbamates and chlorodioxaphospholanes and -phosphorinanes and their reactivity

“…Another synthetic option is the reaction of PCl3 with N-chloroamides of carbonic acid ROC(O)NHCl or N-chloroaminoethers (RO)2C=NCl leading to ROCON=PCl3 which can undergo hydrolysis to yield N-dichlorophosphoryl carbamates [3]. The range of synthetic methods was enlarged when it turned out that unsubstituted phosphorylated carbamates can be formed when phosphorylated isocyanates react with alcohols or mercaptanes [4]. This method can be applied for the synthesis of various types of phosphorylated carbamates.…”

10.1007/s11176-008-1030-1

“…155!156. Proceeding with the development of synthetic approaches to new heterophosphacyclanes with endocyclic P3C bonds on the basis of functional a-substituted alkylphosphonates [4,5], we explored ÄÄÄÄÄÄÄÄÄÄÄÄ the reactions of diphenyl a-(phenylamino)benzylphosphonate I with aromatic and phosphorylated iso-(thio)cyanates. Pudovik, L.K.…”

Reaction of chloromethyliso(thio)cyanato(thio)phosphonates(-phosphinates) with phenol, ethanol, and thiols

“…Previously we showed that phosphorylated carbamates in the presence of bases undergo heterocyclization due to intramolecular interaction of the chloromethyl and carbonyl groups to form unsaturated heterocycles, such as 1,3,2-oxazaphospholines [2]. Aiming at preparing new functionalyzed (chloromethyl)phosphonates and (chloromethyl)thiophosphonates capable of further transformations, we reacted (chloromethyl)iso(thio)cyanatophosphonates-(-phosphinates) with phenol, ethanol, and thiols.…”